Revision of Dicoelia (Phyllanthaceae; Euphorbiaceae s.l.).

Dicoelia was always considered to be a monotypic genus. Typical are the hooded (cucullate) petals that form cavities in which juvenile thecae of adjacent stamens are protected. Specimens of Sumatra appear to represent a new species. The Sumatran specimens have stipules that fall slightly later and they show morphological differences in the pistillate petals, pistillode, columella and hilum. Newly described structures are disc glands (thought to be absent), probably not functional, but present in the flowers of both sexes and a gynophore in the pistillate flowers. Dicoelia is considered as a member of the Phyllanthaceae conforming with the latest molecular phylogenetic results; a classification that agrees with the presence of two ovules per locule. [ABSTRACT FROM AUTHOR]